Method of controlling the operation of an air charging system of an internal combustion engine

Abstract

A method and apparatus is disclosed to control the operation of an air charging system of an internal combustion engine. A plurality of output parameters of the air charging system are monitored. An error is calculated between the monitored output parameters and a target value thereof. The calculated errors are applied to a linear controller that yields a virtual input used to calculate a plurality of input parameters for the air charging system. The input parameters is used to determine the position of a corresponding actuator of the air charging system for operating the actuators according to the determined position thereof. The inputs parameters are calculated with a non-linear mathematical model of the air charging system configured such that the virtual inputs are in a linear relation with only one of the output parameters and vice versa.

What is claimed is: 
     
       1. A method of controlling the operation of an air charging system of an internal combustion engine having an intake duct, a turbocharger with an exhaust gas turbine and a high-pressure exhaust gas recirculation (EGR) loop, comprising:
 monitoring at least three output parameters of the air charging system, wherein the at least three output parameters includes a manifold pressure and a residual gas function in the internal combustion engine; 
 calculating an error between each one of the monitored output parameters and a target value thereof; 
 applying each one of the calculated errors to a linear controller for yielding three virtual inputs; 
 calculating at least three input parameters for the air charging system, using the three virtual inputs with a non-linear mathematical model of the air charging system configured such that each one of the virtual inputs is in a linear relation with only one of the output parameters and vice versa, wherein the at least three input parameters includes an intake mass flow rate; 
 determining a position of a corresponding actuator of the air charging system using each one of the at least three input parameters, wherein the corresponding actuators include a first actuator for an intake valve in the intake duct, a second actuator for a valve in the HP-EGR loop and a third actuator for the turbine; and 
 operating each one of the corresponding actuators according to the determined position thereof. 
 
     
     
       2. The method according to  claim 1 , wherein the input parameters of the air charging system comprise a parameter indicative of an exhaust mass flow rate through the exhaust gas recirculation valve, a parameter indicative of an air mass flow rate through the air intake valve, and a parameter indicative of an exhaust mass flow rate through a turbine of the variable-geometry turbocharger. 
     
     
       3. The method according to  claim 2 , wherein the output parameters of the air charging system comprise a parameter indicative of an exhaust manifold pressure, a parameter indicative of an intake manifold pressure and a parameter indicative of a residual gas fraction in the intake manifold. 
     
     
       4. The method according to  claim 1 , wherein the actuators of the air charging system further comprise an LP-EGR valve actuator. 
     
     
       5. The method according to  claim 4 , wherein the input parameters of the air charging system comprise a parameter indicative of an air mass flow rate through the air intake valve, a parameter indicative of a flow effective area of the first exhaust gas recirculation valve, a parameter indicative of a power rate of a turbine of the variable-geometry turbocharger, and a parameter indicative of a flow effective area of the second exhaust gas recirculation valve. 
     
     
       6. The method according to  claim 5 , wherein the output parameters of the air charging system comprise a parameter indicative of a pressure within an intake manifold, a parameter indicative of a residual gas fraction in the intake manifold, a parameter indicative of a compression rate caused by a compressor of the variable-geometry turbocharger, and a parameter indicative of a residual gas fraction in an intake duct upstream of the compressor. 
     
     
       7. The method according to  claim 6 , wherein the input parameters of the air charging system comprise a parameter indicative of an air mass flow rate through the air intake valve, a parameter indicative of a flow effective area of the first exhaust gas recirculation valve, a parameter indicative of a flow effective area of a turbine of the variable-geometry turbocharger, and a parameter indicative of a flow effective area of the second exhaust gas recirculation valve. 
     
     
       8. The method according to  claim 7 , wherein the output parameters of the air charging system comprise a parameter indicative of a pressure within an intake manifold, a parameter indicative of a residual gas fraction in the intake manifold, a parameter indicative of a pressure within an intake duct between a compressor of the variable-geometry turbocharger and the air intake valve, and a parameter indicative of a residual gas fraction in the intake duct upstream of the compressor. 
     
     
       9. The method according to  claim 7 , wherein the output parameters of the air charging system comprise a parameter indicative of a pressure within an intake manifold, a parameter indicative of a residual gas fraction in the intake manifold, a parameter indicative of a pressure within an exhaust manifold, and a parameter indicative of a residual gas fraction in an intake duct upstream of the compressor. 
     
     
       10. The method according to  claim 7 , wherein the output parameters of the air charging system comprise a parameter indicative of a pressure within an intake duct between a compressor of the variable-geometry turbocharger and the air intake valve, a parameter indicative of a residual gas fraction in the intake manifold, a parameter indicative of a pressure within an exhaust manifold, and a parameter indicative of a residual gas fraction in an intake duct upstream of the compressor. 
     
     
       11. The method according to  claim 1 , wherein each one of the calculated errors is applied to a proportional-integrative controller for yielding the virtual input. 
     
     
       12. The method according to  claim 1 , wherein each one of the calculated errors is applied to a proportional-integrative-differential controller for yielding the virtual input. 
     
     
       13. A non-transitory computer readable medium comprising a computer code, which when executed on a computer, is configured to perform the method according to  claim 1 . 
     
     
       14. An electronic control unit for an air charging system of an internal combustion engine having an intake duct, a turbocharger with an exhaust gas turbine and a high-pressure exhaust gas recirculation (EGR) loop, wherein the electronic control unit is configured to:
 monitor at least three output parameters of the air charging system, wherein the at least three output parameters includes a manifold pressure and a residual gas function in the internal combustion engine; 
 calculate an error between each one of the monitored output parameters and a target value thereof; 
 apply each one of the calculated errors to a linear controller for yielding three virtual inputs; 
 calculate at least three input parameters for the air charging system, using the three virtual inputs with a non-linear mathematical model of the air charging system configured such that each one of the virtual inputs is in a linear relation with only one of the output parameters and vice versa, wherein the at least three input parameters includes an intake mass flow rate; 
 determine a position of a corresponding actuator of the air charging system using each one of the at least three input parameters, wherein the corresponding actuators include a first actuator for an intake valve in the intake duct, a second actuator for a valve in the HP-EGR loop and a third actuator for the turbine; and 
 operate each one of the corresponding actuators according the determined position thereof.